https://www.pcgamer.com/every-oculus-rift-is-offline-thanks-to-an-expired-certificate/

If you're having trouble with your Oculus Rift today, then you're not alone. A certificate linked to the devices has expired and caused them to stop working, with users facing a "Can't Reach Oculus Runtime Service" error if they try to boot up. Oculus is aware of the problem and is working on a fix.

The problem appears to be affecting all users. It was first flagged on the Oculus forums, and some quick digging uncovered the fact that a certificate for the Oculus Runtime Service expired earlier today, which is a pretty big oversight on Oculus's part.